PM, or particulate matter, are tiny solid or liquid particles found in the atmosphere. Particulate matter is considered the most dangerous form of air pollution as the tiny particles can easily be absorbed by the lungs into the blood stream causing many health issues. The International Agency for Research on Cancer and the World Health Organization both consider particulates to be a Group 1 Carcinogen. PM 2.5 are particulates with a diameter of 2.5 micrometers. PM 2.5 particulates are especially dangerous as their small size allows them to penetrate the lungs more easily. We have taken data from the EPA and created a map that shows the mean PM 2.5 levels across the United States. Check out how clean the air is in your city or state below, and keep checking our site for more maps and data on air and water pollution!